Psychiatric and neurological conditions can be extremely difficult to treat effectively because of the multiplicity of symptoms and etiologies associated with such conditions. Current drug therapies have focused on either high selectivity for one pharmacological effect or broad non-selectivity to attempt to provide multiple symptom relief. Therapies that have focused on high pharmacological selectivity have been shown to provide limited benefits for disorders with multiple causes, but can in some cases worsen some symptoms. For example, selective antagonism of dopaminergic receptors for schizophrenia results in a worsening of some negative symptoms as well as in tardive dyskinesia.
Drug therapies having broad non-selectivity, on the other hand, can provide relief for more symptoms but often have more side effects. For instance, current antipyschotic drugs have adrenergic, cholinergic, and histaminergic receptor antagonist activities that are associated with deterioration of cognitive function and other side-effects, such as orthostatic hypotension, dry mouth, blurred vision, constipation, and motor impairment. Regardless of drug therapy selectivity, there remain symptoms, such as cognitive decline, that are not adequately treated by current pharmaceutical compounds used in treating psychiatric and neurological conditions. A need therefore remains for improved pharmaceutical compounds for use in treating such conditions.